<template>
    <p>
        值为:{{count}}
    </p>
    <button @click="add">+n</button>
</template>
<script setup>
import {ref} from 'vue'
const emit=defineEmits(['updateCount'])
const count=ref(1)
const add=()=>{
    count.value++;
    emit("updateCount",2)
}
</script>